<!DOCTYPE html>
<html>

<head>
  <meta charset="UTF-8">
  <title>03_回到顶部</title>
  <style>
    #to_top {
      width: 30px;
      height: 40px;
      font: 14px/20px arial;
      text-align: center;
      background: #06c;
      position: fixed;
      cursor: pointer;
      color: #fff;
      left: 1250px;
      top: 500px;
    }
  </style>
</head>
<body style="height: 2000px;">

<div id="to_top">返回顶部</div>

</body>

</html>